Switching converters are electronic circuits with switches that are capable of a converting an input voltage (Vin) into an output voltage (Vout) with a small loss of power. An example DC-DC switching converter includes an output inductor, an output capacitor, a power stage (with power transistors) and a controller. In operation, the inductor and capacitor filter out the switching signal provided by the power stage. Meanwhile, the controller monitors Vout and provides waveforms to the power stage to maintain regulation on Vout. In many cases, to ensure a stable regulation, the controller can only work with a certain range of output inductors and output capacitors.
Depending on the output power, the power transistors may or may not be placed together with the controller in a single integrated circuit. Also, the output inductor and output capacitor are usually discrete external components due to their size. For cost and flexibility reasons, efforts to provide a controller that can address a wide range of inductors and capacitors. To that end, several techniques are available. In one example technique, the current on the output inductor is measured and is used to adjust a controller or feedback loop. This type of topology is typically referred as a “current mode” converter. The disadvantage of this technique is that the overall gain loop may be reduced by placing this second loop in the system. Another disadvantage is that minimum turn on time or minimum turn off time is not optimal as it is limited by the switching characteristics to resolve to a reliable current reading. In another technique, a user can manually adjust the compensation of the controller. In another technique, a range of output inductors and output capacitors that are compatible with a given controller are identified and provided to a customer. Efforts to improve controller flexibility are ongoing.